I actually tried flying in 9 mph wind just now, it wasn't bad at all, only couple slight shakes, and 1 wind warning when I got up higher. I went out about quarter mile out of sight (houses blocking view), and not in a straight line, but in a pattern, veering off to the right to do some discovery above a park. I used the signal boosters, had excellent signal, I know the area very well so if I went down I'd know exactly what path to follow to find it. I brought it back manually. It was a great feeling to hear the Mavic first (house blocking view) and then see it above me. I've had about 5 short flights so far and this was my farthest one for flying out of sight.
As far as flying back in ATTI mode, I used the flight simulator today for the first time, and I took the drone far out of sight and used telemetry, how Dybiantis mentioned above, and managed to bring it back a few times. I guess to sum this up, if the app crashes, try reconnecting cables, reboot the tablet, if that doesn't connect you, get up high , at least 100 feet or more, to be above the tallest trees, and either RTH, or fly back by telemetry numbers on the RC.